Anyone who says Scourge is better than Kira doesn't know how to use Kira. She survives better by killing much faster than Scourge.

It doesn't matter what stance Scourge is using. You can have him in great gear, dps, or tank, it doesn't matter. Neither set helps him much. I've tried getting him near to player levels of defense, shield, and absorb in tank stance. He still drops way too fast. I've also tried converting him to DPS, and that didn't help him either.

Setting him on a silver mob to compare to Kira is telling. He consistently takes more damage before the mob dies than does Kira in equal level gear.

No melee tank companion is worth much past the 20s. The ranged ones do a better job tanking, and work better as DPS. The heavy armor melee DPS companions work even better than Kira though. For FP farming, I still prefer ranged DPS, like Vette, and Gault, for their AOE.

Oh, the companion tanks in beta were really pretty good. They got an armor bonus, which was really helpful. That was removed before live game, however.